Published online by Cambridge University Press: 31 May 2012
In 1937-38 the Argentine Department of Agriculture initiated an exchange of grasshopper parasite material with the Canadian Department of Agriculture which was engaged in a study of the natural control of grasshoppers in various provinces of Canada. By 1942 it was considered desirable to introduce exotic species of parasites into Canada on as wide a scale as possible, and the temperate regions of South America were selected as being the most promising for a survey. The parts of the temperate zone of South America to which preferential attention was to be given included the countries of Uruguay, Argentina, and Chile. The well known grasslands of the Rio de la Plata area have been partially transformed into one of the world centres for cereal production and as in other parts of the world increased grasshopper populations constitute a major problem in the agriculture of the region. Here species of the genus Dichroplus are frequently pests in the way in which members of the closely related Melanoplus are in North America.